The present invention relates to a method and device for analyzing data, the sequence of which is described by a state machine.
In a network digital data are usually transmitted according to specified rules. One shape such rules may take are so-called protocols. Protocols may be described in the form of SDL diagrams or as state machines. Accordingly a participant in data transfer is always in a certain state of the state machine, proceeding from which he may, if a certain condition is satisfied or if certain conditions are satisfied, change into another state. FIG. 1 shows a simple example of a state machine. It is assumed that the telecommunication participant under consideration is initially in state A. From this state he, if condition a is satisfied, changes into state C. If condition b is satisfied, he changes into state B. Proceeding from state C, depending upon whether condition c or d is satisfied, he changes to state E or state D respectively.
For the analysis of networks for transmission errors, faults or the like, so-called protocol testers are often used. A protocol tester is designed to analyze the data transmitted. According to one technique the analysis takes place during offline operation, i.e., the data transmitted is first loaded into storage and subsequently filtered out by means of software search routines. Depending upon the data found, further data fragments may be selected in steps from the total quantity of the data and analyzed. The disadvantage of this procedure is that it does not enable analysis in real time. From a disproportionately large quantity of data stored, the relevant data have to be sorted out in a very time-consuming manner.
Another procedure is shown in U.S. Pat. No. 5,850,388 issued Dec. 15, 1998 to Craig D. Anderson et al entitled “Protocol Analyzer for Monitoring Digital Transmission Networks”. In order to analyze data in real time, the protocol tester is equipped with several Reduced Instruction Set Computer (RISC) processors and also features hardware filters to filter bit sequences that are previously specified by a user from the incoming data. The disadvantage of this protocol tester is that it involves an enormous amount of hardware which not only impacts on costs, but also on weight and the handiness of the equipment.
What is desired is a method and device for analyzing data which enables analysis in real time, but requires a much reduced amount of hardware.